Patent GB-193841-A (GB)
Title: Apparatus for recording or indicating any quantities or qualities at a distance
IPC: G08C19/02
Filed: 1923-02-20
Abstract: 193,841. Roucka, E. Feb. 22, 1922, [Convention date]. Tell-tale apparatus for recording physical values in which an impulse of energy is periodically produced of which the position in a time interval depends on the value to be recorded and which operates the receiving mechanism, is characterized by the employment in conjunction with the primary value of an auxiliary electric magniture continuously varied within given limits. For recording the difference of temperature between two places, thermo-batteries 6, 8, Fig. 1, in the two places are arranged as shown in series with the coil 12 of a relay and a resistance 62. The resistance 62 is also. included in a circuit including a coil 92 at the receiver operating a recording arm 94 and a source of variable voltage. The variable voltage is obtained from brushes 70 rocked round the commutator 68 of a generator 66, by a cam 16 driven from a generator as shown in Fig. 2. The arm 94 thus moves to and fro in accordance with the movement of brushes 70. The relay tongue 16 normally rests on contact 18, but when the currents in the coil 62 from the thermocouples 6, 8 and the brushes 70 have a given relative strength, the tongue 16 moves to contact 17 and connects a magnet 52, fixed brushes 72 of the generator 66, and a magnet 102 at the receiving station in series. Magnet 52 frees a bell crank lever 44 which is normally held behind a catch 46 on its armature, so that the connection of the relay coil 12 to the resistance 62 is broken at the spring 54 and the tongue 16 falls back. The lever 44 is afterwards restored to its normal position by a cam 58 on the continuously driven shaft 77. Magnet 102 rocks the arm 106 so as to press momentarily the recording arm 94 on to a record strip. In a modification, Fig. 6, for recording alterations in the resistance of a coil 150 due to alteration of temperature, fer example of a fever patient, or to moisture, gas composition &c., the coil 150 together with a resistance 152 continuously varied by means of a cam 190 driven by a motor 194: forms one arm of a wheatstone bridge. A relay 170 connected across the bridge is arranged so that at the moment of balance a circuit 172', 174<1>, 174 is completed, this circuit being broken at other times by the arm 172' or spring 174'. At the receiving station a recording arm is continuously moved synchronously with the slider of the resistance 152., and is pressed into contact with the strip 211 by the operation of a magnet 215 at the instant of completion of the circuit 172<1>, 174<1>, 174. In a further example, Fig. 3, a Ferrari type instrument for measuring current, power &c. carries a conducting pointer 132. A coil 14.2: carrying a continuously varying current as from brushes 70 shown in Fig. 1, carries an arm 138 provided with a cup 136 containing mercury. As the arm 132 moves to and fro, it periodically makes contact with the pointer 132 so as to complete a circuit for a magnet such as 102, Fig. 1, and to cause a synchronously moving arm at the receiving station to be pressed momentarily on a record strip. The coil 142 may be mounted on the same shaft as the pointer 132 so that the force to be measured and the varying force oppose one another. In this case the pointer operates a contact similar to that shown in Fig. 6. The type of contact 138, 136 shown in Fig. 3 may be used with the apparatus shown in Fig. 6 instead of that shown. Specifications 191,395 and 193,398 are referred to.